Forum Discussion

cody8411_186897's avatar
cody8411_186897
Icon for Nimbostratus rankNimbostratus
Jan 29, 2016

Handling www with host name redirects in iRule

I'm trying to figure out how I can handle the following situation.

 

The section of the iRule below is for redirecting to a different URL based on a hostname. Our organization has purchased multiple domain names that are more or less used as shortcuts to a specific URL.

 

For example: companydepartment.com -> http://www.company.com/department/index.html

 

I'm using data groups to facilitate this with a name -> value in a string data group. In trying to optimize the code for this, I've ran into a snag when they want to use www.companydepartment.com.

 

I have to create a duplicate entry for www.companydepartment.com -> http://www.company.com/department/index.html

 

How can I handle this traffic so that both hostname with and without www. will be matched, and also with the understanding that there may be a subdomain to a different URL in some cases www.training.companydepartment.com -> http://www.company.com/department/training.html

 

if {[class match [HTTP::host] eq group_80_host_redirect]} {
    HTTP::redirect [class match -value [HTTP::host] eq group_80_host_redirect]
}

Data group example

 

ltm data-group internal group_80_host_redirect {
    records {
        company.com {
            data http://www.company.com
        }
        companydepartment.com {
            data http://www.company.com/department/index.html
        }
        training.companydepartment.com {
            data http://www.company.com/department/training.html
        }
    }
    type string
}
application delivery
hostname
iRules
LTM
redirect
  • Tim_K_92675's avatar
    Tim_K_92675
    Icon for Cirrostratus rankCirrostratus
    Jan 29, 2016

    If you consistently maintain your data group names without 'www.' then you could pull in the requested hostname, strip off www. if it exists, and then run it through the data group. Something like this (untested)...

    when HTTP_REQUEST {
    if { [string range [HTTP::host] 0 3] eq "www." } {
        set hostname [string range [HTTP::host] 4 end]
    } else { 
        set hostname [HTTP::host]
    }
    if {[class match $hostname eq group_80_host_redirect]} {
        HTTP::redirect [class match -value [HTTP::host] eq group_80_host_redirect]
    }
}
  • Kai_Wilke's avatar
    Kai_Wilke
    Icon for MVP rankMVP
    Jan 29, 2016

    Hi Cody,

    you may try the performance optimized snippet below. It would require just a single data group query to check for existence and to retrieve the location value...

    when HTTP_REQUEST {
    if { [HTTP::host] starts_with "www." } then {
        if { [set location [class match -value [string range [HTTP::host] 4 end] eq group_80_host_redirect]] ne "" } then {
            HTTP::redirect $location
            return
        }
    } else { 
        if { [set location [class match -value [HTTP::host] eq group_80_host_redirect]] ne "" } then {
            HTTP::redirect $location
            return
        }
    }
    HTTP::redirect "https://www.company.com/unknown_hostname/error.html?host=[URI::encode [HTTP::host]]"
}

    Cheers, Kai